Anxiety corresponds to an emotional and unpleasant state of nature associated with tension, stress, apprehension or uneasiness, discomfort and concern or fear about some defined or undefined future threat. Anxiety is commonly characterized by psychological symptoms like lack of concentration, sympathetic and somatic symptoms including tachycardia, tremors, sweating, gastrointestinal tract (GIT) disturbances, etc. Fatigue and sleep disturbances were also found to be common signs of anxiety. Some degree of anxiety is a part of normal life, but if anxiety conditions persist it impairs a person's ability to perform a job and often leads to visceral organ dysfunction and neurological problems.
In anxiety conditions the stress hormone cortisol is being released in large amounts which affects the brain and leads to memory loss and may cause problems related to memory recall. Sleep deprivation which occurs during anxiety also affects a person's memory and even may lead to dementia.
It has been observed that anxiety and memory are two closely related paradigms. Anatomically, brain structures such as hippocampus/amygdala are implicated both in anxiety and memory (Beuzen and Belzung C, Physiology and behavior 58(1); 1995: 111-118.) Anxiety, depression and calming effect are interrelated functions in the brain. For example, administration of THC (Tetrahydrocannabinol) in animals impaired the memory and simultaneously found to increase the symptoms of anxiety. Similar type of effect was found to occur in humans during acute administration of cannabinoids. (O'Shea et al Journal of Pscychopharmcology 18 (4); 2004: 502-508). There are reports that various monoamines (catecholamines) can interfere with memory enhancement and anxiety. Increase in brain serotonergic transmission can interfere with memory and learning acquisition (Niemi P M et al., Acta Psychiatr Scand. 2002; 106: 461-63). The role of 5-HT in anxiety is very clearly established. Increase in brain 5-HT levels leads to anxiety while decrease in brain 5-HT levels leads to anti-anxiety. (Leijdekkers M L et al., Headache. 1990; 30: 352-58).
The symptoms or conditions of severe anxiety should be treated with anxiolytics. Some drugs functions both as anxiolytics and hypnotic agents. Anxiolytics produce a restful state of mind without interfering with normal mental or physical functions. In allopathic treatment, Benzodiazepines category of drugs like Diazepam, Lorazepam, etc. were most commonly used for anxiety disorders. They have good anxiolytic property but show a high tendency to produce amnesia effect both in animals and human subjects. The alternatives used are Azapirones, however these drugs produce both psychological and physical dependence with withdrawal symptoms. To overcome these effects several herbal remedies like kava, passion flowers, valerian, chamomile, lavender, lemon balm etc. had been studied as alternative treatment for anxiety. But these products have limitations of their own. Some may even cause severe side effects like liver damage, confusion, memory decline etc. (Roth et al., J. Clinical Pharmacol. 1984; 18(1 S), 45S-49S). It has been observed that general anxiolytic drugs currently in use have significant adverse effect on the memory of the subject including memory loss or memory impairment.
Sleep disorders are some of the most prevailing health issues around the world, which are very often related to anxiety, stress and depression. Humans sleep approximately one-third of their lives. Though the science of sleep has not fully understood the necessity for sleep and its mechanisms for sleep's physical and mental restoration, sleep disruption or sleep disorders have shown to create fatigue and suboptimal performance causing significant medical, psychological, and social disturbances. Insomnia, the sleep disorder, can be defined as the subjective complaint of impairment in the duration or quality of sleep, characterized by difficulty in falling asleep, difficulty in maintaining sleep, early morning wakening etc. Approximately 35% of the adult population has reported to have insomnia, with chronic problems to nearly 7% leading to anxiety and depression.
Black cumin (Nigella Sativa) seeds and black cumin seed oil prepared by a cold-press method such as an ‘expeller’ are being widely used over centuries for the treatment of various ailments throughout the world. It is one of the important drugs in the Indian traditional systems like Ayurveda and Unani. Many studies on N. sativa suggest that, its biological activity is attributed specifically to the components in the essential oil. So far, many active compounds have been identified and isolated from black cumin seeds. (Ahmad A. Asica Pac J Trop Biomed. 2013; 3(5): 337-352). The oil from the seed is used as a natural protective and curative remedy. N. sativa was reported to contain >30% fixed oil and <0.45% volatile oil. One of the major active constituents present in black cumin seed essential oil is thymoquinone which constitutes about 30-48%, p-cymene (7-15%), carvacrol (6-12%), 4-terpineol (2-7%), t-anethole (1-4%), sesquiterpene longifene (1-8%), etc. Thymoquinone (TQ) which is chemically called as 2-isopropyl-5-methyl-1, 4-benzoquinone, is the most pharmacologically active compound found in black cumin oil (Salim et al., Molecules, 2013; 18(9), 11219-11240). The oil also contains many saturated and unsaturated fatty acids such as linoleic acid, linolenic acid, oleic acid, etc along with alkaloids, Isoquinoline alkaloids (nigellicimine and nigellicimine-N-oxide) and Pyrazol alkaloids or indazole ring bearing alkaloids (nigellidine and nigellicine).
Many toxicological studies have been carried out on N. sativa seeds and its oil and no toxic effects were reported. N. sativa seed powder does not produce any toxic effects even at very high doses (28 gm/kg orally) in rabbits; its oil was also found safe when given orally to rats (LD50 of 28.8 mL/kg). Thymoquinone (TQ), one of the active components in black cumin was usually found in the oil fraction at very low levels of 0.05 to 0.2% w/w. It was found relatively safe when given orally to experimental animals. The LD50 of TQ was found to be 104.7 mg/kg and 870.9 mg/kg in mice followed by an intra-peritoneal injection and oral ingestion respectively. Whereas, LD50 in rats was found to be 57.5 mg/kg and 794.3 mg/kg after intra-peritoneal injection and oral ingestion respectively (Al-Ali, et al, J. Ayub. Med. Coll. Abbottabad, 2008, 20: 252-257). TQ was also reported to be safe in rabbits with an LD50 of 2.4 g/kg (Randhawa, J. Ayub. Med. Coll. Abbottabad. 2008, 20, 1-2).
Existing technologies for extracting thymoquinone containing oil from matured black cumin seeds had various disadvantages like poor yield, use of organic solvents like hexane, chlorinated solvents, methanol, ethyl acetate, etc. Solvents used in the process will further tend to degrade the thymoquinone fractions and make its concentration low. Technologies discussed in the prior-art report poor thymoquinone content of 0.01-0.2% in the extracted oil. These ordinary black cumin seed oil compositions have been reported to produce anti-anxiety activity at a high dose of not less than 3 grams/day or above, however there is no evidence of studies related to its effect on sleep disorders with simultaneous enhancement in the memory of the subject.
U.S. Pat. No. 8,501,250B2: This invention refers to extractions of fixed oil and thymoquinone rich fractions, (containing up to 6% of thymoquinone) from Nigella sativa seeds using supercritical fluid extraction process. However, the invention has not given any details for the preparation of more than 6% thymoquinone containing oils or about its stability and methods for the preparation of stable compositions of thymoquinone rich black cumin extracts in oil and powder form. The invention has also not provided any therapeutic effect on anxiety related disorders and memory enhancement or safety have not been studied.
US 2011/0076346A1 discloses supercritical extraction of black cumin seeds to prepare oil fractions containing 0.01 to 40% thymoquinone and its antioxidant, thermogenic, anti-inflammatory effects. However, the invention has not provided any input regarding the yield of thymoqunine rich fractions of oil that can be produced by the present method. The invention also reported a low percentage thymoquinone content (2.95%) at 100 g level and 39.3% at 100 Kg under same conditions of process. However, no explanation has been given for this unexpected thymoquinone recovery at higher scale, which usually not common. The invention provided a method of just physical blending of thymoquinone rich oil with the powder of the spent material obtained after supercritical extraction. However, no information about its stability is provided, since thymoquinone is a component of the volatile fraction of the oil and is highly oxidisable. Moreover, no information about its brain health functions, or mechanism of action or dosage is provided.
WO2015/086239A1 is directed to thymoquinone or thymoquinone comprising compositions for use in the treatment of neurodegenerative diseases such as Parkinson, Huntington and Alzheimer's disease, however there is no indications for the use of said compositions in combination with anxiolytic properties.
WO2010/133574A1 describes the invention of N. sativa oil derived compounds like thymoquinone for the use as an opioid receptor stimulating compound for the treatment or prevent food allergy. The invention has used lipid extract of black cumin containing only 0.22% (w/w) of thymoquinone. No information regarding its process of manufacturing, other composition of the lipid fraction under investigation, safety features, and plausible effects of high thymoquinone fractions were mentioned.
WO2010/050794A1 describes the invention of antioxidant N. sativa oil fraction for the treatment of hypercholesterolemia, as demonstrated by the in vitro and in vivo effects of anti-atherogenic, anti-hypolipidemic activities. No information regarding its thymoquinone content, composition, etc are available.
US2012/0244234A1 discloses the use of N. sativa extracts for the treatment of symptoms connected to impaired neurotransmission in animals and humans and their use as food/feed supplements. Though the patent has pointed out the serotonin—reuptake inhibition effects of black cumin oil containing 0.01% thymoquinone, and its plausible positive effects on people who are under chronic or acute stress, no information has given on the effect of thymoquinone content or about the process of manufacture of high thymoqunone rich oils and its possible stable formulations and further applications to brain health including sleep disorders. Moreover, they have used an organic solvent extraction process to prepare the oil. The patent has not revealed any suitable composition of the N. sativa seeds or its method of preparation or its safety profile for the use of brain health functions, especially with regard to anxiolytic effects with memory enhancement. It does not provide any quantitative data or measurement of its effectiveness in animal or human models to prove its efficacy.
US2011/0076346A1 describes supercritical fluid extracts containing 0.01 to 40% w/w of thymoquinone and their antioxidant, thermogenic, anti-inflammatory activities as useful as nutraceutical supplements for conditions that include obesity, asthma, hypertension, diabetes, inflammation, cough, bronchitis, head ache, eczema, fever, dizziness etc. However, no information regarding the most effective composition for optimum brain functions such as sleep disorders, depression, cognition impairment, stress, anxiety etc have been mentioned.
US2008/0152736A1, US2003/0060454A1, US2003/0060508A1, US2005/0214241A1 describe an invention related to a lipid composition of black cumin to treat/prevent skin infections, wounds, bacterial infections, respiratory diseases, cellulite, cardiovascular diseases, septic infections etc. The invention includes the fractionation of oils into saturated, unsaturated, glycerol esters, volatile fractions etc. and its topical formulations. No information regarding thymoquinone or its neurological effects has been given.
US2002/0132019A1 describes a sterol fraction of black cumin oil and its applications in fungal and bacterial infections, vaginal diseases and disorders by making use of its anti-inflammation, pain reliving or anti-allergic properties.
U.S. Pat. No. 6,218,434B1 describes the use of N. sativa derived thymoquinone and dithymoquinone in the treatment of parental and multi-drug resistant human cancers.
Chemically synthesised thymoquinone has been reported to produce memory improvement in a dose dependent manner (Roghani et al. Pejouhandeh. 2012; 17(5): 219-227). However it has also been observed that a high dosage of thymoquinone produces toxicity and is harmful to human beings. However, no information on black cumin or its possible effects on brain functions were disclosed.
Hence there exists a need to develop a green process for the extraction of thymoquinone rich black cumin seed oil suitable for safe and convenient oral delivery at 50 to 250 mg dose/day to produce satisfactory efficacy on human subjects experiencing anxiety, stress, depression, sleep disorders, memory decline etc. It has been anticipated that extract compositions comprising thymoquinone at about 2 to 45% w/w and preferably about 2 to 25% w/w, more preferably 2 to 10% may be of great use. There also exists a need to develop a safe herbal nutraceutical composition based on thymoquinone rich black cumin seed oil, effectively useful for the treatment of anxiety conditions, which also exhibits simultaneous memory enhancement effect.